Apparatus for closing a lifting propulsion unit chamber



June 24, 1969 A. BUCHSTALLER 3,451,647

APPARATUS FOR CLOSING A LIFTING PROPULSION UNIT CHAMBER Sheet Filed Oct. 18, 1965 INVENT OR ANTON BUCHSTALLER ATTORNEY J1me 1969 A. BUCHSTALLER 3,

APPARATUS FOR CLOSING A LIFTING PROPULSION UNIT CHAMBER Filed Oct. 18, 1965 Sheet 2 of 2 ANTON BUCHSTALLER BY W I CIA- ATTORNEY United States Patent 3,451,647 APPARATUS FOR CLOSING A LIFTIN G PROPULSION UNIT CHAMBER Anton Buchstaller, Friedrichshafen, Germany, assignor to Dornier-Werke G.m.b.H., Friedrichshafen (Bodensee), Germany, a corporation of Germany Filed Oct. 18, 1965, Ser. No. 497,277 Claims priority, application Germany, Nov. 26, 1964, D 45,921 Int. Cl. B64b 1/24 US. Cl. 244-53 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an apparatus for closing a discharge opening in a lift engine bay containing a lift engine and having a spoiler flap mounted at the front of the opening, the apparatus also including a closing flap pivotally mounted at one side of the opening, and an auxiliary flap pivotally mounted beside the opening and opposite the closing flap.

The lift engines of hovering aircraft, where the latter are jet-borne hovering aircraft, conventionally are mounted in lift engine bays- It is also known to utilize propulsion engines for lifting purposes.

The present invention is concerned with the so-called genuine lift engines which serve only to produce the lifting force. These genuine lift engines are accommodated either in bays in the fuselage of the aircraft or in special lift pods mounted on the wings. As a consequence of the peculiarities of take-off and landing operations of hover ing aircraft using gas jet lift engines, the bottom flaps of the lift engine bays serve not only to close the bays but also are used for other purposes. It has been proposed, for example, that when starting the lift engines while the aircraft is on the ground, the lift engine bays be used for laterally deflecting the gas jets from the aircraft so that the gas jets do not too strongly impinge on the ground, with the result that no dirt and dust are whirled up and sucked. in by the lift engines. According to this known proposal, the closing flaps of the lift engine bays are made tiltable or pivotal and are pivoted or swung into the gas jets for the purpose of deflecting them. This is useful,

however, only when starting the lift engines while the aircraft is on the ground prior to take-off.

A problem which has not been solved in a satisfactory manner heretofore arises when starting the lift engines while the aircraft is in flight. Since the air under the lift engine bays produces a dynamic pressure, starting of the lift engines becomes diflicult. In such case, a low pressure area is required at the discharge of the lift engines during the starting operation. An aircraft is known to the art having lift engines in the fuselage thereof wherein the lift engine bays are covered or closed by means of two side flaps of identical size. In order to produce a low pressure area during the start-up of the lift engines While the aircraft is in flight, a spoiler flap is mounted forward of each bay. As a result of the combined action of the spoiler flap with the side flaps of the lift engine bays, a low pressure area is formed below the lift engines. Totally neglected in this solution are, however, the conditions which exist during the start-up of the lift engines while the aircraft is on the ground, i.e., a deflection of the gas jets is not effected and particles of dirt can be whirled up and sucked in by the lift engines.

The present invention avoid-s the disadvantages and drawbacks of the aforementioned known mechanisms for closing the bays of lift engines and provides a closing mechanism which is equally suitable for start-up of the ice lift engines while the aircraft is on the ground as well as in flight. In the present invention, a bottom flap is employed for closing or covering the bay, which flap is pivotal about a hinge mounted at one side of the bay. The flap may be locked in position in the propellant gas jet in order to deflect the gas jets of the lift engines. The construction of the present invention also includes a spoiler flap, of known construction, which is mounted forward of the bay opening and an additional auxiliary flap which is pivotal about a hinge mounted at the other side of the bay opening, i.e., opposite the closing flap. During the closing operation, the auxiliary flap is pivoted into the lift engine bay and during the transitional phase of the aircraft, it is locked in an approximately vertical position. The bottom flap closing the bay thus may be utilized for deflecting the propellent gas jets when the aircraft is standing on the ground and the engines are running. During the start-up operation while the aircraft is in flight, a low pressure area below the lift engines is produced as a result of the combined action of the bottom flap, the spoiler flap, and the auxiliary flap. In this case, the auxiliary flap prevents the influx of the dynamic air from the side.

All three flaps can be locked in three positions in which they are coordinated to each other. In the first position, the bottom flap closes the bay opening, the auxiliary flap is pivoted into the bay, and the spoiler flap is retracted for the remainder of the time the aircraft stands on the ground and for the duration of the normal horizontal flight. The lift engine bays are thus covered and no additional aerodynamic resistance occurs during flight. In the second position, which is coordinated to the start-up of the lift engines while the aircraft is on the ground, the bottom flap is opened approximately half Way, the auxiliary flap is fully pivoted laterally outward-1y, and the spoiler flap is extended about half the maximum distance thereof. The propellent gas jets are laterally deflected in this position of the flaps. The third position is employed for starting the lift engines while the aircraft is in flight. In this case, the bottom flap and the auxilary flap are in a position pointing approximately vertically downwardly and the spoiler flap rests or nearly rests against the end edges of the two aforementioned flaps. As a result, a rearwardly open box, which causes the formation of a low pressure area, is formed below the lift engine bays.

In a further feature of the present invention, the pivoting movements of the flaps may be coupled with one another. The bottom flap and the auxiliary flap are connected with each other by means of an operating or control linkage and are actuated by a servomotor. In a particularly simple construction the opera-ting or control linkage of the bottom flap and the auxiliary flap consists of an articulated lever, one lever member of which is pivotally mounted, with the outwardly positioned end thereof, at one chamber wall and the other lever member of which is pivotally connected to the bottom flap. The servomotor acts, for the purpose of moving the articulated lever, on a toggle joint on the lever and a connecting rod, having an energy source therein, is secured between the articulated lever or an arm thereof and the auxiliary flap. In the control linkage, the pivot point of the connecting rod at the articulated lever, or arm of the latter, passes, during pivoting action of the bottom flap and the auxiliary flap, through a straight line connecting the pivot point of the articulated lever on the chamber wall and the pivot point of the connecting rod on the auxiliary flap. The width of the auxiliary flap is approximately equal to half the width of the chamber opening.

The invention will be further illustrated by reference to the accompanying drawings in which:

FIGURE 1 is a front view of the lower portion of a lift engine nacelle showing one embodiment of the present invention in the open position thereof,

FIGURE 2 is a view in cross-section through the lift engine nacelle of FIGURE 1 showing three different positions of the bottom flap and the auxiliary flap, and

FIGURE 3 is a side view showing the position of the spoiler flap with respect to the bottom flap and the auxiliary flap.

The embodiment shown in the drawing is a lift engine bay 1 in a lift engine nacelle 2. It is possible to accommodate the lift engine bay in the fuselage of an aircraft instead of a nacelle, if desired, Several lift engines are mounted in the bay 1 in a series arrangement. FIGURES 1 and 3 show the jet nozzles 3 of the lift engines in dashed-dotted lines.

In FIGURE 1, the lift engine bay 1 is open and the bottom flap 4 asumes an approximately vertical downwardly-pointing position. During the opening and closing operations, the bottom flap 4 pivots about the hinge pin 5. Mounted at the opposite lower edge of the chamber 1 is the hinge pin '6 for the auxiliary flap 7, which latter also points downwardly. The extended spoiler flap 8 is mounted forward of the bay 1. In these positions, all three flaps are looked in position for hovering flight and for starting the lift engines while the aircraft is in flight. A low pressure area will be formed below the lift engines in the latter case. In the construction illustrated, the armate bottom flap 4 is additionally provided, at the end edge thereof, with a screening plate 9 which fills the interspace between the bottom flap 4 and the spoiler flap 8. In case the configuration of the nacelle 2 is different or in case the bay 1 is positioned in the fuselage of an aircraft, the spoiler flap 8 may be so constructed that the screening plate 9 is omitted.

FIGURE 2 shows the bottom flap 4 and the auxiliary flap 7 in the three primary positions in which they are locked. The spoiler flap mounted forward of the bay opening, and being adapted to be adjusted by means of a separate servomotor, has not been shown in the interest of greater clarity in the drawings. Shown in solid lines are the bottom flap 4 and the auxiliary flap 7 in the positions they occupy when the bottom of the lift engine bay 1 is closed. In this case, the auxiliary flap 7 will be positioned in the bay directly over the bottom flap 4. Illustrated in dashed-dotted lines are the flaps in the position they occupy when the gas jets are laterally deflected by the bottom flap 4. The auxiliary flap 7 is pivoted outwardly so that it does not obstruct the path of the gas jets. Shown in dashed lines are the flaps in the position described above in connection with FIGURE 1. In this case, the gas jets are discharged without obstruction in the downward direction and the aircraft can begin jetlever system. The piston rod of the servomotor is pivotally secured to the toggle joint 16 of an articulated lever having the lever arms 12 and '13. The end of the lever arm 12 is connected to the wall of the bay by the pivot pin 14 and the end of the lever arm 13 is connected to the bottom flap 4 by the pivot pin 15. By retracting the piston rod of the servomotor 10, the articulated lever is moved in the downward direction and the bottom flap, 5s a result, is opened. The articulated lever includes an arm 17 to which is pivotally connected a connecting rod 18 which includes a source of energy such as a compression spring, for example; the connecting rod 18 moves the auxiliary flap 7. The energy source, i.e., the spring in the connecting rod, has the effect that at the beginning of the opening operation, the auxiliary flap will remain in a substantially horizontal position so that a striking of the auxiliary flap 7 and the bottom flap 4 against one another is effectively prevented.

FIGURE 3 shows a part of the nacelle 2 in a side view with the flaps open. The bottom flap in the foreground and the auxiliary flap 7 positioned behind it are completely extended. The spoiler flap 8 is pivoted about the hinge pin 19 and abuts against the front edges of the bottom flap and the auxiliary flap.

What is claimed is:

I. In combination, an engine bay, a vertically mounted lift engine in said bay, the bay including an exhaust opening in the bottom thereof, closure means for selectively closing off said exhaust opening, said closure means including a bottom flap pivotally supported at one side of said opening for closing off said opening, an auxiliary flap pivotally supported at the other side of said opening, and a spoiler flap movably supported forwardly of said opening, and operating means for locking all of said flaps in three operative positions including: a first position wherein said bottom flap closes said exhaust opening; a second position wherein the bottom flap is opened approximately half way, the auxiliary is fully pivoted laterally outwardly to laterally deflect propellant gas and the spoiler flap is extended about half the maximum distance thereof; and a third position wherein said bottom flap and said auxiliary flap are positioned approximately vertically downwardly and the spoiler flap is extended and positioned adjacent the forward edges of said bottom flap and said auxiliary flap to define a rearwardly open box causing the formation of a low pressure area below said bay when in flight.

2. Apparatus as defined in claim 1 wherein said bottom flap has a width at least equal to that of said opening and said auxiliary flap has a width substantiall less than that of said opening.

3. Apparatus as defined in claim 2 wherein said auxiliary flap has a width approximately half that of said exhaust opening.

4. Apparatus as defined in claim 1 wherein said operating means includes an articulated lever including a pair of lever arms, one of said arms being connected with the side of said bay and the other of said arms being connected with said bottom flap, power-operated means connected between the side of said bay and said lever, and a connecting rod connected between said lever and said auxiliary flap whereby said bottom flap and said auxiliary flap are operated simultaneously.

5. Apparatus as defined in claim 4 wherein said connecting rod has a compression spring connected therein for delaying opening movement of the auxiliary flap.

6. Apparatus as defined in claim 4 wherein the point of interconnection between said lever and said connecting arm during pivoting action of the bottom flap and the auxiliary flap passes through a straight line connecting the point of connection of said lever with the side of said bay and the point of connection of said connecting rod with said auxiliary flap.

' References Cited UNITED STATES PATENTS 2,822,996 2/1958 Von Zborowski 60-230 X 2,928,238 3/1960 Hawkins 244-52 3,033,493 5/1962 Wilde et al 24452 X 3,134,226 5/1964 Gardner et al 60229 X 3,155,342 11/1964 Bolkow et al. 244-52 X 3,186,661 6/1965 Denning et al. 60-229 X 3,258,206 6/1966 Simonson 244-23 X 3,302,889 2/1967 Di Sabato 239265.39 X 3,042,342 7/1962 Wiles et al. 24423 3,223,354 12/1965 Seibold et al. 244l2 3,327,482 6/1967 Pike 60271 MILTON BUCHLER, Primary Examiner.

JAMES E. PITDENGER, Assistant Examiner.

U.S. c1. X.R. 

